Rare earth-containing frits having a high glass transition temperature and their use for the production of enamels having improved heat resistance.

摘要

The present invention is directed to an alkali borosilicate frit which is capable of being applied to a metal substrate by the dry powder electrostatic process at a transfer efficiency of at least 70%, has a glass transition temperature of 525° C. and contains, based on the total weight of the frit:PP ______________________________________ PP Oxide Wt % PP______________________________________ PP K. sub.2 O 6 to 10 PP Na.sub.2 O 5.5 to 9 PP LiO.sub.2 0 to 4 PP ZrO.sub.2 0 to 4 PP TiO.sub.2 0 to 4 PP ZnO 0 to 15 PP B.sub. 2 O.sub.3 PP 8 to 15 PP SiO.sub.2 40 to 60 PP La.sub.2 O.sub.3 PP 3 to 9 P P CaO 0 to 15 PP F 0 to 2 PP Fe. sub.2 O.sub.3 PP 0 to 3 PP CoO 0 to 5 PP NiO 0 to 5, PP ______________________________________ PPP Pwherein the total weight of CoO plus NiO is at least 1.P PThe present invention is also directed to enamels for self-cleaning ovens containing these frits.